78 lines
2.0 KiB
Bash
78 lines
2.0 KiB
Bash
#!/bin/bash
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shopt -s extglob
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m4_include(common)
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usage() {
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cat <<EOF
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usage: ${0##*/} chroot-dir [command]
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-h Print this help message
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-u <user>[:group] Specify non-root user and optional group to use
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If 'command' is unspecified, ${0##*/} will launch /bin/bash.
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EOF
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}
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chroot_add_resolv_conf() {
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local chrootdir=$1 resolv_conf=$1/etc/resolv.conf
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# Handle resolv.conf as a symlink to somewhere else.
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if [[ -L $chrootdir/etc/resolv.conf ]]; then
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# readlink(1) should always give us *something* since we know at this point
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# it's a symlink. For simplicity, ignore the case of nested symlinks.
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resolv_conf=$(readlink "$chrootdir/etc/resolv.conf")
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if [[ $resolv_conf = /* ]]; then
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resolv_conf=$chrootdir$resolv_conf
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else
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resolv_conf=$chrootdir/etc/$resolv_conf
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fi
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# ensure file exists to bind mount over
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if [[ ! -f $resolv_conf ]]; then
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install -Dm644 /dev/null "$resolv_conf" || return 1
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fi
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elif [[ ! -e $chrootdir/etc/resolv.conf ]]; then
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# The chroot might not have a resolv.conf.
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return 0
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fi
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chroot_add_mount /etc/resolv.conf "$resolv_conf" --bind
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}
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while getopts ':hu:' flag; do
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case $flag in
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h)
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usage
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exit 0
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;;
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u)
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userspec=$OPTARG
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;;
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:)
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die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
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;;
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?)
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die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
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;;
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esac
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done
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shift $(( OPTIND - 1 ))
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(( EUID == 0 )) || die 'This script must be run with root privileges'
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(( $# )) || die 'No chroot directory specified'
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chrootdir=$1
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shift
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[[ -d $chrootdir ]] || die "Can't create chroot on non-directory %s" "$chrootdir"
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chroot_setup "$chrootdir" || die "failed to setup chroot %s" "$chrootdir"
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chroot_add_resolv_conf "$chrootdir" || die "failed to setup resolv.conf"
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chroot_args=()
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[[ $userspec ]] && chroot_args+=(--userspec "$userspec")
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SHELL=/bin/bash unshare --fork --pid chroot "${chroot_args[@]}" -- "$chrootdir" "$@"
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